Electric emulsion treater with high-voltage entrance bushing and lead-in



April 7, 1959 L. c. WATERMAN 2,881,125 ELECTRIC EMuLsIoN TREATER WITH HIGH-VOLTAGE ENTRANCE BUSHING AND LEAD-IN Filed Aug. 2a, 195o 2 Sheets-Sheet 1 /NVEL/v Tof?. Loca-AN C. WHT/PMA/v SY H/s ATTORNEYS. v Heek/5, K/chg Fos TER a; Heee/5 April 7, 1959 l.. c. WATERMAN 2,881,125

ELECTRIC EMULSION TREATER WITH HIGH-VOLTAGE ENTRANCE BUSHING AND LEAD-IN Filed Aug. 28, 1950 2 Sheets-Sheet 2 LOGAN C. WATERMAN BY H/S ATTORNEYS. Hmm/5, K/EcH, Fos Ta/: Hmm/5 United States Patent O M' 'ELECTRIC EMULSON TREATER WITH HIGH-VULTAGE ENTRANCE BUSHING AND LEAD-3N Logan C. Waterman, Houston, Tex., assigner to Petrolite Corporation, Wilmington, Del., a corporation of Delaware Application August 2S, 1950, Serial No. 181,760 4 Ciaims. (Cl. 204-302) ly, the safe and fool-proof transmission of high voltages to the interior of an electric emulsion' treater from a `transformer mounted thereon. It should be understood,

however, that the invention can be used in other fields kwhere it is desirable that high-voltage currents should be ltransmitted between spaces or containers which may be at diiierent pressures or which may give rise to ashover ditiiculties due to the presence of imperfect iiuid dielectrics such as contaminated oils, etc.

Conventional electric treaters are adapted to resolve oil-continuous emulsions, the internal phase being usually an aqueous medium, such as water, brine, acid sludge or other reaction product. Such treaters usually include a pressure-type container and at least one inlet bushing for conducting a high-voltage energizing potential to one or more electrodes within the container and submerged in a body of oil-continuous liquid therein. The emulsion to be treated is introduced into the container to be acted upon by a high-voltage iield established by the electrode means, the ield usually coalescing the dispersed aqueous phase into masses of sufficient size to set- 'tle in the container, leaving the oil-continuous body of treated oil in the upper end of the container. This separated oil-continuous material still contains some of the dispersed aqueous medium, usually in the form of minute droplets or masses that have not gravitated from the oil. The oil-continuous material may also contain other contaminating substances, some of which may be dissolved inthe oil. Even though the amount of such contaminating substances is relatively minute, entrance bushings extending into such a body of oil-continuous material or into a gas-iilled pocket opening thereon are subject to deterioration to such an extent that service calls most frequently involve bushing trouble.

The conventional electric-treater bushing, almost universally used as a result of years of experience in trying numerous other types, has a vulcanized or cured body of rubber-impregnated silica molded around a conductor and carrying a porcelain cap exposed to the weather outside the treater, this cap Ibeing cemented to the body. A mounting iiange is provided for securing the bushing in place with the lower exposed end of the body extending inside the container in communication with the treated oil. The external surface of this lower or inner portion of the body is exposed to the oil and its dispersed aquous medium or contaminating substances and usually extends in contact therewith throughout a portion or all of such exposed surface.

The temperature and pressure at which an electric 2,881,125 Patented Apr. 7, 1959 treater can be operated are limited largely by the bushingr employed. Conventional bushings soften with increase in temperature so that excessively high internal pressures must be avoided, particularly at elevated ternperature, as mechanical failure of the bushing may permit jetting of high-temperature oil into the air above the treater with consequent severe tire hazard. Additionally, conventional bushings will not only melt at elevated temperature but may even burn in the presence of any external fire, any such mechanical failure representing a hazard to `be avoided.

l't is an object or the present invention to provide a bushing that will resist mechanical failure to a degree heretofore unattainable and that will permit use of treater temperatures as high as S50-400 F. and internal pressures up to 1000 p.s.i. or more at such temperatures without failure.

While conventional bushings sometimes fail mechanically, the most frequent cause of trouble is from electrical failure. This usually arises from current iiow through leakage paths along the exposed surface of the bushing, the current flow varying from a very small value up to an arcing condition. The heat developed oxidizes or burns into the surface of the bushing, requiring removal of the bushing and replacement either by a new bushing or by a similarly-burned bushing which has been turned down in a lathe to present a new exposed surface.

Any current leakage through or along the surface of suc-h a bushing will tend to interfere with the desired electric treatment, even though there is no heavy arcing along the surface. Thus, conventional electric treaters employ a high-voltage source of potential connected in series with a choke coil to reduce the voltage applied to the electrode means with any increase in current. Correspondingly, leakage currents decrease the potential applied to the electrode means and the intensity of the iield employed for coalescing the dispersed particles of the incoming emulsion into masses of suicient size to gravitate from the oil.

The internally exposed surfaces of conventional bushings are not immune to, and often receive, deposits of the residual dispersed phase material or deposits of sulphides, sulphur compounds, inorganic salts, sludgelike materials or other extraneous materials. The formation of such deposits in electric-treater bushings is accelerated or induced by the presence of an electric field radiating from the conductor of the bushing which is at high potential relative to the container or any other grounded portion of the equipment. This iield is more intense at positions adjacent the exposed surface of the bushing than at positions more removed therefrom so that some of the suspended aqueous medium or other contaminating substances in the oil will be attracted to the zone of higher gradient adjacent the exposed surface to form deposits thereon. Irrespective of how such deposits form, surface contamination of the bushing by materials extracted from the oil is a serious problem and results in leakage currents along or adjacent the exposed surface of the bushing.

Conventional bushings are also senstive to voltage surges or transient voltages which are set up during the treatment of certain oils. Such transients may impose voltage gradients on the bushing several times the intensity of those which would normally be expected on the basis of the power source employed. Even minor contaminations on the bushing surface may lead to electrical failure under conditions of electric surging and substantial diniculty has been encountered with conventional bushings when such surging conditions exist.

Additionally, leakage currents along the bushing or other insulating means may give rise to or be the cause of surges. The electrode means of an electric treater represents a capacitive load which, coupled with the impedance of the supply circuit, may produce a resonant circuit in which high Voltage currents may surge if initiated by any transient condition, such as an increase in current in the electric iield or even an increase in leakage currents through or along the insulation means. In the electric treatment of emulsions it is desirable to eliminate such surging, and the insulator arrangement of the present invention tends to decrease surging and give better emulsion treatment. Even under surging conditions arising from sources other than leakage along or through the insulator means, the present invention has been found to withstand voltage surges` without electrical breakdown or arcing along the exposed surface of the insulator means.

It is an object of the present invention to provide a bushing structure overcoming such diiiculties as are enumerated abovel and which can extend in an environment containing contaminating substances while minimizingdanger of liash-over. A further object is to provide a bushing having a surface formed of a material which is immune to and not wettable by oil, any suspended aqueous medium therein, or any component of the oil or aqueous medium. It is a further object to utilize' a polymerized uoroethylene material in this connection, preferably polytetrafluoroethylene or polytrifluorochloroethylene.

In prior entrance bushing designs, a single insulating member was employed around a conducting rod and was required to resist the dielectric stress as well as the mechanical stress, serving as a support for terminal ends of the rod disposed respectively inside and outside the container. In prior practice, such an insulating member wassubject both to dielectric puncture and to surface flash-over.

It is an important object of the invention to provide a bushing structure in which that portion which is subject to dielectric puncture is separate from that portion which is subject to surface flash-over. Another object is to provide separate elements respectively designed to resist puncture and flash-over stresses; also to use one element for taking mechanical stresses and another for taking electrical puncture stresses.

In prior designs, any high-voltage lead was connected to the outer terminal end of the rod at a position exposed to the atmosphere, thus giving rise to corona losses and representing an extremely serious hazard to personnel. Additionally, the outer portion of the bushing was subject to ash-over as its surface became contaminated by dirt or exposure to moist atmospheric conditions.

It is an object of the present invention to provide a. completely enclosed lead-in system protected against ash-over, corona losses and accidental contact. A further object is to provide such a lead-in system which can be easily replaced without exposing the contents of the container to the atmosphere and often without any unpressuring of the container.

A further object of the invention is to use a highvoltage cable extending through the container and having its terminus at a position within the container. In this connection, it is an object of the invention to provide an electric treater or other device in which a cup-like insulating member extends inward from a wall of the container and provides a contact means at its inner end electrically connected to the end of a high-voltage cable. A further object is to provide a contact means comprising contact members which are readily separable and connectible, usually brush-type contact members compensating for any differential expansion between the cable and its surrounding insulating member and also permitting connection and disconnection of the contact members merely by forcing the cable into the cup-like or surrounding insulating member and pulling it therefrom.

It is another object ofV` the invention to employ an insulated high-voltage cable extending between two containers with its ends exposed to the interiors thereof, one container housing a source of high-voltage potential and the other container housing electrical equipment. A related object is to employ a flexible metal-shielded cable in this connection with the shield electrically connected to both of the containers to act as a ground and to protect against accidental contact that might lead to electrocution.

A further object is to extend a conduit, preferably a length of pressure tubing, between such containers, the cable extending therethrough and the interior of the conduit or tubing forming a space into which any leakage from either container will be confined. Another object is to seal the cable relative to such a conduit or tubing in at least one position to impede any leakage between containers or from a container into the conduit or tubing.

Further objects and advantages of the invention will be evident to those skilled in the art from the following description of an exemplary embodiment of the invention used for energizing an electric treater from a high-voltage transformer.

Referring to the drawings:

Fig. 1 is an elevational view of such a system with a. portion of the treater broken away;

Fig. 2 is an enlarged cross-sectional view of the upper portion of the lead-in system of Fig. 1;

Fig. 3 is an enlarged vertical sectional view of the lower portion of the lead-in system of Fig. 1;

Fig. 4 is an enlarged fragmentary view of the elements enclosed in dotted circle A of Fig. 3; and

Fig. 5 is an enlarged elevational view of a section of the pressure tubing with its contained high-voltage cable.

Referring particularly to Fig. 1, the lead-in system is indicated generally by the numeral 10 and serves to conduct high-voltage currents from a iirst container 11, which may represent the housing of an oil-filled high-voltage transformer 12, to a second container 13, illustrated as the tank of a conventional electric emulsion treater 14. The transformer 12 is mounted above the treater 14 on a platform 15 supported by an upper wall 16 of the container 13. This container also provides a lower Wall 17.

Within the treater 14 is an electrode means, diagrammatically shown in Fig. 1 as including an upper electrode 20 suspended from the upper wall 16 by a rod 21 in which is interposed a string of suspension insulators 22. Below the electrode 20 is a lower electrode 23 which may be at ground potential or any potential other than that of the upper electrode 20 with the end in view of establishing a high-voltage electric iield in a treating space 24 between the electrodes. The upper and lower electrodes may be of any suitable design, as, for example, the electrodes disclosed in the patent to Harold C. Eddy, No. 2,182,145.

The incoming emulsion to be treated is of the waterin-oil type and is pumped in heated condition through an inlet pipe 25 and a riser pipe 26 to a distributor 27 which jets the emulsion radially outwardly in the treating space 24 where the dispersed aqueous material is electrically coalesced into masses of sufficient size to gravitate from the oil. The electrically treated emulsion constituents separate in the container 13 to form a lower water-continuous body 28 withdrawable through a pipe 29 equipped with a back pressure valve 30, and form an upper oilcontinuous body 31 from which material may be withdrawn through a pipe 32 equipped with a back pressure valve 33. There may or may not be a layer `of sludge or unresolved emulsion 34 between the bodies 28 and 31. Such a treater is ordinarily operated under superatmospheric pressure of 25-50 p.s.i. or more by throttling the back pressure valves 30 and 33. Correspondingly, the lead-in system 10 and its inlet bushing structure 35 should be designed to resist the internal pressure of the con- JAM,

tainer 13, any leakage of hot oil into the atmosphere being very dangerous. The lead-in system should also be designed to prevent transfer of oil-continuous material from the container 13 to the transformer container 11 or vice versa. The transformer elements, indicated by the numeral 36, are submerged in a body of transformer oil having a level above the point of connection of the lead- `in system 10.

Generally speaking, the lead-in system 10 includes a length of conduit or pressure tubing 40 enclosing a highvoltage cable 41 having end portions 42 and 43 extending respectively into the interiors of the containers 13 and 11. The end portion 42 extends into a tubular member 45 ydepending in the container 13. A first connection means 46 connects the inner or lower end of the tubing 40 to the container 13 and to the tubular member 45 in a manner best shown in Fig. 3. A second connection means 47 'connects the upper or outer end of the tubing 40 to the container 11 in a manner best shown in Fig. 2.

Fig. l shows the tubular member 45 as depending in Athe container 13 through an opening 50 of the top wall 16, the opening 50 being formed by a flanged member 51 welded to the container 13. Mating with this flanged Vmember and suitably secured thereto, as by bolts, not shown, is a anged member 52, the upper internallythreaded neck of which is shown in Fig. 3.

Referring now to Fig. 3, this internally-threaded neck -of the hanged member 52 threadedly receives an adaptor or connector member 53 having a hexagonal portion 54 -and an externally-threaded neck 55. The connector member. 53 includes a passage 56 which ilares at 56a into a lower threaded counterbore 57 and which is enlarged at its upper end into a tapered sealing zone bounded by an upwardly diverging wall 58.

The upper or outer end of the tubular member 45 is open and externally threaded to be screwed tightly into the threaded counterbore 57, usually leaving a chamber '59 between such end and the are 56a. This connection forms substantially the sole support for the tubular member l45, this member being thus supported as a cantilever.

The tubular member 45 has an external surface 60 exposed to the body of oil-continuous material 31 and 'to kany contaminating substances contained therein. This 'tubular member 45 is preferably a cylindrical piece of :insulating material, being preferably relatively massive to Aprovide walls of sufficient thickness to resist the pressure :'in the container 13. One function of the tubular member -45 `is to serve as a means for shielding the inner end por- 4tion 42 of the cable 41 from the direct internal pressure `within this container. For this and other reasons the llowermost end of the tubular member 45 should be closed.

This closure is preferably effected by a terminal means for terminal structure shown as including a metallic closure member 61 having a threaded cavity 62 tightly receiving the threaded lower or inner end of the tubular VSrnember 45 and electrically connected by a conductor 62a to the rod 21 and thus to the upper electrode 24). 'In addition, the terminal means is shown as including slidably engaging terminal members 63 and 64 to facilitate engagement and disengagement and also to permit relative sliding upon any relative change in length of the Sinner portion 42 of the cable and the tubular member 45, `as by differential expansion when subjected to elevated temperatures The terminal member 63 faces the interior 'of the tubular member 45 and provides a flange 65 clamped between the bottom of the closure member 61 `and the end of the tubular member 45. Its upwardlyextending portion provides a neck with a tapered sur- 'face 66 serving to guide the lower end of the terminal member 64 into a cavity 67 with which it forms a rela- Vtively tight fit to provide good electrical contact. The terminal member 64 is soldered to the terminal end of `the conductor 68 of the high-voltage cable 41.

The'tubular member 45 provides a passage 69 which, =With 'the passage 56, Areceives the inner end portion 42 of the cable, preferably leaving a small annular space 70 around the cable. This anular space 70 is preferably filled with a uid dielectric medium, preferably silicone grease, to avoid the presence of a gas-containing space or pocket subject to the formation of corona and serving as a pressure-transmitting medium to increase the sealing action of a sealing structure now to be described. If desired, however, the annular space 70' may be iilled with a semi-solid or solid dielectric such as sulphur, litharge, etc.

The upper end of the annular space 70 is sealed by a sealing means at or adjacent the junction of the cablef41 and the wall 16 of the container. The preferred structure includes an annular compressible sealing member 71 surrounding and engaging the smooth periphery of the inner end portion 42 of the high-voltage cable and of an initial form shown in Fig. 3. In this form, the sealing member 71 has a lower tapered surface conforming to the upwardly diverging wall 58. Its lowermost end provides a surface 72 exposed to the annular space 70 and against which the silicone grease will press to increase the sealing action upon any increase in pressure in the annular space 70. The surface 72 may be in direct or indirect pressure-transmitting relationship with the annular space 70.

The sealing member 71 may be formed of asbestos or other sealing material and is compressed by the lower of two union members 73 and 74 which with a pipe member 75 form a conventional pipe union. The pipe member 75 has the usual llange 76 and sealing end 77 which are brought into contact with corresponding surfaces of the union member 73 when the union member 74 is tightened. The union member 73 is threaded to the neck 55 of the connector member 53 and carries an annular member 78 welded in place as at 79 and providing a curved surface 80. This surface corresponds in shape to the ared end of a corona shield 82, this flared end lying between the surface 80 and the sealing member 71. Correspondingly, upon tightening the union member 73 on the neck 55 the sealing member 71 is compressed by the corona shield 82 and the annular member 78 to form an effective seal for the high-voltage cable. As previously mentioned, the sealing action lwill be increased by any increase in pressure in the annular space 70 as by any small contraction of the tubular member 45 when subject to the internal pressure of the container 13.

The high-voltage cable 41 is preferably of a special construction described as follows. Around the central conductor 68 thereof is wound, layer on layer and with a substantial overlap, a plurality of turns of polymerized fluoroethylene material in tape form with a silicon filler between the turns. This type of layer-on-layer construction is suggested in the lower portion of Fig. 3 with the tape-like material being indicated by the numeral 85, the combined turns building up a sheath of polymerized uoroethylene material 86. Around the sheath 86 is woven a glass braid or cover 87. As initially manufactured, the cable 41 has an outer cover 88 comprising a braided metallic shield, the complete cable being relatively iiexible.

In the present invention, the cable 41 must resist the dielectric puncture stress of the high-voltage current, wherefore the sheath 86 should be formed of a material of high resistivity and good dielectric properties to resist puncture between the conductor 68 and those grounded portions of the cable or of the equipment which are immediately around the sheath 86. On the other hand, a separate element is employed to resist flash-over, namely, the tubular member 45. This makes it possible to design the two elements to serve best their respective functions.

While in many less exacting installations the sheath 86 and the tubular member 45 may be formed of various dielectric media, the use of polymerized uoroethylene has been found to have unexpected actions and results when the sheath 86 andthe tubular member 45 are made therefrom, particularly when the bushing structure is employed in conjunction with an electric treater. The preferred materials are, first, polytetrauoroethylene (available under the trademark Teflon) and, second, polytriuorochloroethylene (a product commercially available under the tradename Kel-13).

Polytetrafluoroethylene is a polymerized tetrafluoroethylene, the thermo-dynamically unstable monomer being transformed by the polymerization into an extremely stable polymer of remarkable chemical inertness which does not dissolve or swell in any of the various acids or alkalines. The material has a wax-like feel and is unwettable by oil, aqueous materials or chemical substances to such an extent that no known adhesive will bond permanently two sheets of the material, albeit some degree of success has been obtained by bonding under heat and pressure. The material has a dielectric constant of about 2.0. In sheets of only a few thousandths of an inch in thickness, its dielectric strength is about 1500 volts/mil. Other materials are known having higher dielectric strengths and dielectric constants, and the new material is not used -in the present invention primarily because of -any unexpectedly high dielectric values. Instead, its use in forming the tubular member 4S has shown unexpected superiority in view of its surface characteristics, being wettable neither by oil, water nor any component of the emulsion. The desirable surface characteristics make possible the avoidance of surface leakage through surface deposits that would otherwise form on the external surface 60, which deposits would be conductive and would represent a discontinuous layer between the dielectric material and the uid therearound.

Additionally, polytetrauoroethylene is a completely fluorinated and completely oxidized material. In use, as herein described, no evidence of any major surface arc has ever been observed. If any arc did form along the external surface 60 or through the oil immediately therebeyond, there would be no carbonizing and no carbonaceous material would be formed to bond to the surface. Additionally, and very importantly, the material will withstand desirable treater temperatures as high as S50-400 F. with desirably high internal pressures of 350-250 p.s.i. and higher at such temperatures without failure. Finally, the material will not burn in the presence of an external lire, the construction of the present invention also protecting the material from such external fire and preventing failure of the sealing action of the sealing member 71.

In preparing the cable 41 for use in the equipment shown, the braided metallic shield, forming the outer cover 88, may be cut back to terminate within the pipe member 75, leaving the glass braid or cover 87 intact throughout the length of the inner end portion 42 which extends through the corona shield 82, the sealing member 71 and the passages 56 and 69. The corona shield 82 has a tapered portion 90 which is slipped under the end of the braided metallic shield forming the outer cover 88, as best shown in Figs. 3 and 4. A length of copper Wire 91 is wound with contacting turns about the metallic braid, starting from the end of this braid and extending a distance beyond the tip of the corona shield 82. This Wire is wound suiciently tight to deform the braided metallic shield inwardly at the tip of the corona shield 82, as suggested by the numeral 92 in Fig. 4, thus tending to prevent corona formation to or from this sharp tip. The wire is then sweated in place by applying solder.

Alternatively, it is within the scope of the invention t extend the braided metallic shield, forming the outer cover 88, through the sealing member 71 which is compressed therearound in sealing relationship. The corona shield 82 and its wrapped junction with the outer cover 88 will then be in the passage 56 with its llared end in the chamber 59 in contact with the are 56a of the connector member 53 and being pressed thereagainst by the upper end of the tubular member 45 which is then desirably shaped to conform to the are of the corona shield.

The high-voltage cable 41 preferably extends Within the pressure tubing 40. In the preferred embodiment, this pressure tubing is llexible, being made of a helical metal strip wound around an inner tube of rubber or other llexible material in turns which loosely interlock to provide exibility. This is suggested in Fig. 5 in which the adjacent interlocking turns are indicated by the numeral 94, the rubber lining tube being indicated by the numeral 95, and loosely surrounding the outer cover 88 of the cable to provide a small annular space 96. This tubing may be of any known type, preferably of an armored construction to provide a continuous ground between the containers 11 and 13.

The lower end of the tubing 40 is connected by solder 97 to a male coupling 98 threaded into a bushing 99 which in turn is threaded into the pipe member 75.

The second connection means 47 for connecting the upper end of the lead-in system '10 to the transformer 12 is best shown in Fig. 2. The upper end of the tubing 40 is cut back as shown and terminates in a chamber 100 formed in a collar member 101. Threaded to this collar member is a gland 102 engaging a packing keeper 103, turning the gland 102 compressing an asbestos or other packing 104 tightly around the end of the tubing 40. The collar member 101 is threaded into a bushing 105 which in turn is threaded into a connector member 106 to compress an annular sealing member 107 around the outer braided cover 88 of the cable 41. The sealing member 107 may be formed of the same material as the sealing member 71 and likewise presents a surface 108 exposed to the annular space 96 so that any increase in pressure in this annular space will tend to increase the sealing action by further compression of the sealing member 107 around the cable 41.

The connector member 106 provides a threaded portion 109 which extends through an opening 110 of a wall 111 of the transformer container 11. A nut 112 threaded to the portion 109 compresses a gasket 113 against the wall 111 to form a fluid-tight joint.

The braided metallic shield, forming the outer cover 88 of the cable, is cut back to terminate a short distance above the connector member 106, a corona shield 115 being bound in place as previously described, this corona shield providing a flared portion 116 which diverges in the oil environment of the transformer container 11. The upper end portion 43 of the high-voltage cable extends to the transformer 36, the central conductor 68 being surrounded by the sheath 86 and its glass braid cover 87 substantially to the high-voltage winding of the transformer.

The sealing member 107 seals the transformer oil from the annular space 96, but if any oil leakage should occur, it will be into the space 96 and not into the atmosphere. Any such leakage into the space 96 will quickly build up a pressure therein which will oppose the pressure head of the oil in the transformer to prevent further leakage.

Similarly, the sealing member 71 forms a seal between the annular spaces 70 and 96. If there should be any leakage of oil-continuous material from the pressured container 13 into the annular space 70, the pressure in this space will increase to increase the sealing action of the sealing member 71, as previously described. However, even if some leakage should take place upwardly through the sealing member 71, such leakage will be conned in the annular space 96. The tubing 40 is preferably designed to withstand the pressure in the container 13, and any leakage into the annular space 96 will quickly build up the pressure therein to oppose further leakage through the sealing member 71.

Heretofore it has been considered difficult to elect a good seal around a smooth-surfaced high-voltage cable at the point where it enters a pressure container. This is particularly true of a cable sheathed with polytetrauoroethylene which has a Wax-like surface resisting attempts to hold the cable in place frictionally. By way of example, in the absence of the tubular member 45, the internal pressure of the container 13 would tend to force the cable 41 outwardly through the sealing member 71. The tubular member 45 thus acts somewhat as a pressure shield. Even if it contracts slightly under pressure to increase the pressure in the annular space 70, any minute shifting of the cable in the sealing member 71 will relieve the pressure in the annular space. Additionally, the cable 41 tends to be anchored by the corona shield 82 which is xedly positioned and which retains the outer braided cover 88 from movement.

It will be appreciated that the lead-in system can be easily disconnected from the containers 11 or 13 to facilitate inspection. Additionally, by uncoupling the union 73, 74 the lower end portion 42 of the cable can be withdrawn from the tubular member 45 even without unpressuring the container 13. The invention provides for the irst time an electric treater with a cup-like structure, formed for example by the closed-ended member 45, depending in the container and providing separable contact means at a position within the container. The entire lead-in system is closed and sealed from the atmosphere. The high-voltage lead is also protected in all of its portions from accidental contact. Very importantly, the use of uoroethylene polymers for insulation purposes has eliminated practically every diliculty previously encountered in using conventional bushings in an electric treater.

While the present invention has been particularly described with relation to a lead-in system for an electric emulsion treater, it will be apparent that the principles herein disclosed are applicable to numerous other installations wherein high-voltage currents are to be transmitted from container to container or compartment to compartment. The invention nds particular utility in systems wherein pressure differential may exist between the compartments or where flash-over difficulties are encountered in one or both compartments due to the presence of contaminating substances.

I claim as my invention:

l. In combination in a system for electrically treating oil-continuous emulsions containing dispersed-phase contaminating substances: an electric emulsion treater including a first container, spaced emulsion-treating electrodes in said first container, and means for electrically insulating said electrodes from each other whereby a high-voltage electric eld can be established in the interelectrode space to coalesce the dispersed-phase contaminating substances into masses of suiiicient size to settle in said first container and produce a body of treated oil in an upper zone thereof, said treated oil still containing some dispersed contaminating substances; a high-voltage source providing a second container having a terminal portion spaced from said lirst container by an atmospheric zone; pressure tubing extending through said atmospheric zone and having spaced ends; a connector member and means for detachably attaching same to said first container, said connector member providing an opening facing toward the interior of said first container and toward said body of treated oil; first means for connecting one end of said tubing to said connector member to communicate interiorly therewith; second means for connecting the other end of said tubing to said second container for said high-voltage source; a high-voltage insulated cable extending from the interior of one container to the interior of the other through said tubing; a substantially-rigid tubular member supported as a cantilever inside said rst container from said connector member, said tubular member being formed of a material selected from the class consisting of polytetrafluoroethylene and polytritluorochloroethylene and providing an external surface exposed to the dispersed contaminating substances of said treated oil in said upper zone; and a metallic closure member closing the innermost end of said tubular member in pressure-tight rela-s tionship and electrically connected to one of said electrodes, said tubular member and said metallic closure member resisting the pressure in said first container and protecting said cable from the direct application of said pressure, said cable extending into and along the interior of said tubular member and providing an end electrically connected to said metallic closure member.

2. An apparatus as defined in claim 1 including an annular mass of compressible sealing material contacting said cable and said connector member and forming a fluid-tight barrier between the interior of said tubular member and the interior of said pressure tubing, and means for compressing said mass of sealing material against said cable and said connector member.

3. An apparatus as deiined in claim 2 in which said high-voltage cable provides an outer shielded cover formed of metal, and including a corona shield having a ared portion in contact with said annular mass of compressible sealing material, said corona shield being electrically connected to said shielded cover of said high-voltage cable.

4. In combination in an apparatus for electrically treating oil-continuous emulsions containing dispersedphase contaminating substances: an electric emulsion treater including a container, spaced emulsion-treating electrodes therein, and means for electrically insulating said electrodes from each other whereby a high-voltage electric field can be established in the inter-electrode space to coalesce the dispersed-phase contaminating substances into masses of sutiicient size to settle in the container and produce a body of treated oil in an upper zone of said container, said treated oil still containing some of said contaminating substances dispsered therein, said container providing a wall bounding said upper zone; a high-voltage source of potential positioned adjacent said container, said source being enclosed in a second container; an impervious substantially rigid tubular member providing upper and lower ends, said tubular member being formed of a material selected from the class consisting of polytetrauoroethylene and polytriuorochloroethylene; a terminal means closing the lower end of said tubular member and electrically connected to one of said electrodes; a connector member and means for detachably connecting same to said wall of said treater container, said connector member providing a portion connected to the upper end of said tubular member in fluid-tight relationship and communicating interiorly therewith, such portion holding said tubular member in a position extending into said treater container and exposed to surface contamination by collection of said contaminating substances of said treated oil on the exterior of said tubular member; a high-voltage cable: extending between and having end portions extending respectively within said containers, said cable comprisingy a conductor electrically connecting said source and said terminal means and comprising a sheath surrounding said conductor and extending respectively into said tubular member and said second container; a sealing means at each end of said cable respectively sealing said sheath to said connector member and to said second container; a pressure tubing of sutlicient strength to withstand the pressure in said electric-treater container, said tubing surrounding said cable and being of a length to extend between said containers; a connecting means connecting one end rof said tubing to said connector member; and means for connecting the other end of said tubing to said second container.

References Cited in the file of this patent UNITED STATES PATENTS 1,718,817 Greene June 25, 1929 1,794,750 Ainsworth Mar. 3, 1931 (Other references on following page) 11 UNITED STATES PATENTS Burnham Mar. 31, 1931 Smith May 8, 1934 Calvert July 7, 1936 Winograd etal July 6, 1937 Machlett et al Apr. 21, 1942 12 Brodie June 27, 1944 Havlicek Jan. 2, 1945 Meyerhans Mar. 19, 1946 Turner Dec. 9, 1947 Wilson Sept. 19, 19,50 Street May 19, 1953 

1. IN COMBINATION IN A SYSTEM FOR ELECTRICALLY TREATING OIL-CONTINUOUS EMULSIONS CONTAINING DISPERSED-PHASE CONTAMINATING SUBSTANCE; AN ELECTRIC EMULSION TREATER INCLUDING A FIRST CONTAINER, SPACED EMULSION-TREATING ELECTRODES IN SAID FIRST CONTAINER, AND MEANS FOR ELECTRICALLY INSULATING SAID ELECTRODES FROM EACH OTHER WHEREBY A HIGH-VOLTAGE ELECTRIC FIELD CAN BE ESTABLISHED IN THE INTERELECTRODE SPACE TO COALESCE THE DISPERSED-PHASE CONTAMINATING SUBSTANES INTO MASSES OF SUFFICIENT SIZE TO SETTLE IN SAID FIRST CONTAINER AND PRODUCE A BODY OF TREATED OIL IN AN UPPER ZONE THEREOF, SAID TREATED OIL STILL CONTAINING SOME DISPERSED CONTAMINATING SUBSTANCE; A HIGH-VOLTAGE SOURCE PROVIDING A SECOND CONTAINER HAVING A TERMINAL PORTION SPACED FROM SAID FIRS CONTAINER BY AN ATMOSPHERIC ZONE; PRESSURE TUBING EXTENDING THROUGH SAID ATMOSPHERIC ZONE AND HAVING SPACED ENDS; A CONNECTOR MEMBER AND MEANS FOR DETACHABLY ATTACHING SAME TO SAID FIRST CONTAINER, SAID CONNECTOR MEMBER PROVIDING AN OPENING FACING TOWARD THE INTERIOR OF SAID FIRST CONTAINER AND TOWARD SAID BODY OF TREATED OIL; FIRST MEANS FOR CONNECTING ONE END OF SAID TUBING TO SAID CONNECTOR MEMBER TO COMMUNICATE INTERIORLY THEREWITH; SECOND MEANS FOR CONNECTING OTHER END OF SAID TUBING TO SAID SECOND CONTAINER FOR SAID HIGH-VOLTAGE SOURCE; A HIGH-VOLTAGE INSULATED CABLE EXTENDING FROM THE INTERIOR OF ONE CONTAINER TO THE INTERIOR OF THE OTHER THROUGH SAID TUBING; A SUBSTANTIALLY-RIGID TUBULAR MEMBER SUPPORTED AS A CANTILEVER INSIDE SAID FIRST CONTAINER FROM SAID CONNECTOR MEMBER, SAID TUBULAR MEMBER BEING FORMED OF A MATERIAL SELECTED FROM THE CLASS CONSISTING OF POLYTETRAFLUOROETHYLENE AND POLYTRIFLUOROCHLOROETHYLENE AND PROVIDING AN DXTERNAL SURFACE EXPOSED TO THE DISPERSED CONTAMINATING SUBSTANCE OF SAID TREATED OIL IN SAID UPPER ZONE; AND A METALLIC CLOSURE MEMBER CLOSING THE INNERMOST END OF SAID TUBULAR MEMBER IN PRESSURE-TIGHT RELATIONSHIP AND ELECTRICALLY CONNECTED TO ONE OF SAID ELECTRODES, SAID TUBULAR MEMBER AND SAID METALLIC CLOSURE MEMBER RESISTING THE PRESSURE IN SAID FIRST CONTAINER AND PROTECTING SAID CABLE FROM THE DIRECT APPLICATION OF SAID PRESSURE, SAID CABLE EXTENDING INTO AND ALONG THE INTERIOR OF SAID TUBULAR AND PROVIDING AN END ELECTRICALLY CONNECTED TO SAID METALLIC CLOSURE MEMBER. 